Stiffening of shoe uppers and stiffening elements therefor



Feb. l2, 1957 R. a, HARRISON Erm. 2,780,879

STIFFENING oF SHOE URPERS AND STIFFENING ELEMENTS THEREFOR Filed Nov.16, 1953 IN VENTORS nitcd States Patent STIFFENING OF SHOE UPPERS ANDSTIFFENING ELEMENTS THEREFOR Raymond B. Harrison, Arlington, and RussellG. Edwards, Quincy, s., assignors to Stedfast Rubber Company, Inc.,Boston, Mass.

Application November` 16, 1953, Serial No. 392,302 2 Claims. (Cl.i6-46.5)

This invention relates to the stiilenng of a portion of the upper of ashoe. More particularly, it pertains to means and procedure `by which astiiening blank containing a rubber composition can be maintained limpduring the upper assembly and shoe lasting operations and become fullyvulcanized in lasted shape to a permanently resilient condition while inthe iinished shoe and before wear. Y

The invention is applicable to box toes, counters, and other similarstiifening elements. It may best be understood by describing itsapplication to box toes for which it has been employed with outstandingsuccess.

Self-conforming box toes are generally classified as rigid and soft Therigid type includes all kinds, whether thermoplastic, or solventactivatable, or water activatable, that produce iir-m toe Wallsand domeportions upon dissipation of the activating medium used to soften thebox toe blank to a condition of workable plasticity directly before shoelasting operations. The soft types comprise all box toes that do notultimately become fully rigid in the shoe. They embrace a wide range ofcommercial box toe sheet materials providing a variety of degrees ofsoftness or exibility for the shoe manufacturers choice. They aredescribed by the shoe industry as soft, semi-soft, flexible andsemi-ilexible in order to classify these many box toe materials by theend character of the lasted toe in terms of specific degrees ofresilience. The degrees of resilience vary with the box toe materialitself, the latex or other cement used to attach the box toe to shoeparts, and the cementing technique used. The range extends from alifeless softness to a degree of rmness just short of rigidity, andconsidered exible only by reason of the yielding of thel dome and wallportions to thumb pressure to an extent sufficient to locate the toes ofa wearer within the shoe.

All soft box toes, except certain light weight pyroxylin types that areself-adhering upon activation by solvent, must be cemented into the shoeupper. Various cements are employed for this Vpurpose and the cementingtechniques vary widely in accordance with the value of the shoe and thepersonal preference of the shoe manufacturer. In most cases, la-texcements of natural or synthetic rubber are used to attach the box toe toone or more of its co-engaging shoe parts. In some cases, box toes arecementedA on one side with latex and attached thereby to the esh of theleather upper in the stitching room, and again cemented on the oppositeside at the pulling-over operation to `engage and permanentlyV affix theshoe lining thereto. A brush applied, naphtha-rubber cement is oftenemployed for this purpose at the pullingover operation.

Where box toes are cemented into unlined footwear latex cements arealmost universally used in preference to the more viscous naphtha-rubbercements.

These attaching cements have an important bearing on the resilience andstrength of the finished lasted box toe. lf of proper viscosity, theirlilms aid and support 2,780,879 Patented Feb. l2, 1957 the impregnantused in Vthe box toe itself and their eiec- Itiveness in causing the toeto be permanently integrated with the co-engaging shoe parts causes theentire structure of vamp, box toe and shoe lining to become a laminate,thus greatly increasing the box toe wall strength. Many lightweight soitbox toes having ilannel or other textile bases depend nearly as muchupon the iilms which attach the box toe to the shoe lining and/ or shoevamp as upon the box toe itself for the support given the finishedlasted toe.

Box toe sheetngs containing either natural or synthetic rubber as theprincipal component of the impregnant used have always been made eitherpartially or fully vulcanized in their finished state, though the liquidirnpregnant employed has been either entirely uncured or only partiallycured such as in the case when impregnants are constructed frompre-vulcanized latices. Box toes cut from partially vulcanized box toesheetings do not function in the shoe with any degree of permanencethough offering theY advantage of being more readily conformable atlasting operations than box toes cut from fully precured sheetings. Afully precured box toe, being non-thermoplastic and being unactivatableby any solvent not injurious to other shoe parts cannot be softened to acondition of limpness or static pliability directly before the Shoelasting operations, and permitted to set-up through dissipation of theactivating medium as is common practice in preparing rigid box toe typesfor pulling over and bed-lasting. A fully precured box toe tights Vtheconforming action of the bed-lasting wipers and often develops unsightlypin wrinkles in the exterior wall of the shoe toe.

In all shoes which are toe lasted with latex cement and in which theattachment of the overlasted margin of the toe portion of the upperdepends upon the latex cement alone for permanent engagement to theinsole, the active resilience of the fully precured box toe attemptingto return to unlasted shape often acts instantly to pull away from thepartially .coagulated cementiilm applied to the surface ofthe insoleonly seconds earlier.

Therefore, while the finished soft box toe shoe would Y be greatlyenhanced by the complete curing of the rubprovidingit with a box toe orother upper stiieningelement embodying fully cured rubber materialVhavingV a high degree `of permanent resilience, and yet at the same timeavoiding all problems of conforming such ele-V ments to the shoe lastand of varying or increasing shoe manufacturing operations,v or costs,such as derived from the customary practices followed in incorporatingfully cured orpartially cured box toes or similar stiffening elements.

In the accomplishment of this general objective there has beendevelopeda shoe stiiening sheet material impregnated with an uncured rubber and acuring agent, from which to cut the skive box toes, counters, and thelike for incorporation in the upper of a shoe through the use of variousrubber cen-rents containing self-curing, migratory vulcanizingaccelerators operative at room temperatures. Particularly advantageousin use and commercially available arethe dithiocarbamate type roomtemperature accelerators. In one special instance to be mentioned theuse of the curing agent is unnecessary.

Vulcanization or curing of the impregnant composition does not loccur atroom temperature until the dithiocarbamate or other accelerator migratesfrom the adtoe. thus bringing together the sulphur or a curing agent land the accelerator essential for self-curing of the rubber. Variousperfecting agents may be used with the sulphur to enhance' the powerfulaction ofthe dithioca-rbamate on the rate of reaction between rubber andsulphur. The irnpregnant composition is thus changed physically from aplastic condition to a resilient mass creating a lively rebound in thetoe structure.

It is a further and specic object of this invention to provide shoestiffener sheet material of the character indicated with an auxiliarysaturantor coating that will add a different uncured rubber component tothe sheet material for preventing blocking or welding of the sheetmaterial to itself particularly while being dinked or cut. The shoestiffener sheet material having such an auxiliary saturant or coatingfor preventing blocking or Welding is the subject of our copendingapplication Serial No. 629,988, tiled December 2l, 1956.

These and other features of the invention will be particularized andmore fully understood from the following detailed descriptions ofpreferred embodiments, when taken in connection with the accompanyingdrawing in which:

Fig. l is a plan View of a cut and skived toe stiffener blank formed ofthe sheet material of this invention;

Fig. 2 is a plan view of the inside of the toe portion of a shoe vamp towhich the toe stiifener blank of Fig. l has been partially applied inthe required position by means of adhesive;

Fig. 3 is a plan view of the outer side of a quarter lining partiallycovered by a counter stiiening blank,l made in accordance with thisinvention, and adhesively joined thereto;

Fig. 4 is a perspective view of the quarter lining of Fig. 3 with thecounter stiffening blank adhesively secured to the outer side thereof,the assembly being partially formed to shape for incorporation in theheel end portion of a shoe;

Fig. 5 is a side view of the toe end portion of a lasted shoe ofconventional type welt, partially sectioned to show the last and detailsof box toe construction;

Fig. 6 is a similar side view of the heel end portion of a lasted shoeof welt construction, sectioned to illustrate details of counterstiifening construction; `and Fig. 7 is a bottom perspective View of alast to which a welt insole has been attached, and in which` a liningincluding upper assembly is having cement manually applied to the liningface of the toe blank immediately prior to the pulling-over operation. Y

In the drawing, 10 refers to the toe stiffener blank which has a skivededge portion 12, and refers to the counter stifener blank having aperipheral skived edge portion 22 interrupted Vby a dart 24 forpreforming with a quarter lining 26 by use of stitching 28 as shown inFig. 4.

The shoe stiffener sheet material fromy which the toe i stifener blank10 and the Vcounter stiffener blank 20 are formed may be made of anysuitable base material such as carded felt, napped or unnapped woventextiles, paper and the like, although only the use of a preferredannelyard goods will be described in detail. Entirely suitable finished sheetmaterials in a desired range can beV produced from four basic flannelshaving yardtopound relationships of 4.18, 3.00, 2.35 and 1.60.

In actual practice ideal results have been obtained by the use of twosaturations and a iinal spread coating on one side of the saturated basematerial. pears desirable because it has been found diiicult to obtainthe ounce load required with a single saturation. Further, Y

a second saturation permits. the use of aidiiferenteompound, which,though subject to full curing by the room temperature acceleratorscontained in the cement, acts to decrease the tendency of the iinishedstiiener sheetY to block to other adjacent sheets, as would occur inpackaging and also in cut box toe and counter blanks when die cut inmultiple thicknesses on a beam dinker or clicking. ma-

Double saturatingfap-y 4 chine. Final insurance against blocking isobtained by spread coating a l'm of the nraterial` comprising the secondsaturating compound on one side of the finished sheet goods. It ispossible, however, to obtain adequate impregnation of the saturable basematerial with only a single saturation of either saturating.` compound.

An exemplary formula for the rst saturating compound is as follows:

F rst Saturant Parts by Trade Weight; Naines Crude Rubber (smokedsheet)v 100 10 Amborex-S.

Zinc Oxide 5 Calcium Carbonate.. 90 Atounto. Titanium Dioxide 15Antioxidant i Antox.

Petroleum Naphtha 200 Denatured Alcohol 6 In the above formula, which isa preferred one, the vulcani'zed vegetable oil may range from l0 to 20parts, the sulphur from 2 to 3.5 parts, the zinc oxide from 5 to l0parts, and lthe inertfcalcium carbonate particlesfrom 30 to l5() parts.GR-S synthetic rubber (butadiene-styrene copolymer) may be used in placeof the crudo rubber pro viding the sulphur is increased, to 4 5 to 5parts.

It will be noted that the above compound includes, in addition tosulphur and' other vulcanizing agents, a predominant amount of cruderubber and a very substantial portion of calcium carbonate which acts asa filler. Other lrubbers may be employed in the unvulcanized form.

This rst saturating compound may be made by premas ticating the cruderubber'on a rubber mill and thereafter adding the other solidingredients until all are uniformly milled together. Usiugthe petroleumnaphtha asl a solvent for'the rubber andv denatured alcohol as aviscosity reducer, the mill'ed material is finally churned to aviscosity suitable for saturation.

The second'saturatingcompound which is used also as a ilnalV spreadingcompound differsk in that the predominant elastomeric component is anunvulcanized synthetic rubberwhich is a rubbery copolymer of butadieneand acrylonitrile. YThis compound, an exemplary formula of which is asfollows, also contains a substantial portion of aresinous copolymerof'styrene and butadiene:

' Second; satura/1t'nnd'spreadng compound In the preceding formulan,which is a preferred one,v the zine'oxid'e may range from 2 to- 10parts, the sulphur from 2.5 to 3.5' parts, the styrene-butadienecopolymer from l0 to 35 parts, the calcium carbonate yfrom 20. to70parts, the steari'c 'acid1from l to 2, parts, and the wax from 4 to-part's. l Y

In this instance the compound may be'produced by permasticating thesynthetic butadiene elastomer on a rubber mill, land thenVaddingallother solid' components until a. uniformly milled condition isobtained. Employing toluol as a solvent, the milled material i`s churnedto a suitable saturating or spreading viscosity.

It has been found that an entirely satisfactory shoe stiffening blankmaterial is obtained by saturating and coating a 1.60 double-nappedflannel with the above compounds in the following manner: The flannel issaturated with the saturant of the first compound, `and thereafter itproceeds through a drier having a temperature of the order of 180 F. Thethus dried saturated material in rolled form is then fed to the secondsaturant, after which it also travels through a drier having atemperaturecf the order of 180 F. This roll of dried, double saturatedbase material is then fed through a knife spreader, which imparts alightcoating to one surface only, using the same compound employed in thesecond saturating treatment. The spreading operation is continuous andthe base material coated with the spreading compound proceeds through adrying zone having a temperature of the order of 190 F.

The room temperature, ultra-accelerators that will ultirnately contactthe surface of the finished box toes, counters, and like shoe stifieningelements will cure both the natural and synthetic rubbers of the twosaturating compounds. The particular reason for using the crude rubberimpregnant iirst is that more bounce, as a characteristic of thefinished box toe, develops from the finally cured crude than from thefinally cured synthetic rubber. The uncured crude rubber, however, isslightly tacky and prone to weld or block to itself. By using it as afirst impregnant and then covering it with the second impregnantcomprising a synthetic rubber which, though curable, has much lesstendency to weld in its uncured state, welding of either uncured sheetgoods or uncured cut shoe stiffener blanks is successfully avoided. Itis possible also to use only the second saturant compound by followingthe previously described procedure with the second saturant compoundused for each impregnation. The resulting cured box would havemoderately less life and bounce as compared to one embody ing the cruderubber saturant. In this connection it will be rec-alled that the shoestiffening, sheet material will in each instance remain uncured until itis incorporated into the shoe with accelerator-laden cement.

lt has been found that an ideal latex cement can be made from thefollowing exemplary formula:

Parts by Trade Names Weight Natural latex (60% Solids) 167.0 PotassiumHydroxidc 0. 5 Water-dispersible vulcanizing aceeler- 30.0 Setsit- (R..'l. ator (a dithiocarbamate). Vanderbilt). W ater 65.

Since a latex cement is used on the leather en aUin side ofthestiffening blank, the ultra-accelerator must be dispersible by ballmilling or must be water soluble in order to be miscible with thenatural latex. Dupont accelerators 89 and Tepidone have been tested andfound i to satisfy these requirements as well as the others involved.Tepidone is a 47% water solution of sodium dibutyl dithiocarbamate,according `to Dupont.

An entirely satisfactory naphtlra-rubberv cement has been produced fromthe following exemplary formula:

It is permissible to use from l5 to 30 parts of the accelerator in theabove formula.

Denatured alcohol may also be used in the above formula.

The foregoing naphtha-rubber cement compound isA produced by masticatingcrude rubber on a cold rubber mill, after which the batch is put intosolution with a petroleum naphtha having a distillation range of 204-220 F. and a Kauri-Butanol index of 45. A closed churn is used for.this purpose to prevent solvent loss. The vulcanizing ultra-acceleratoris added after the cement is fully churned to blended smoothness, afterwhich further churning is continued until the vulcanizing accelerator isuniformly mixed throughout the cement which, when finished, shouldcontain l8l9% rubber and have a viscosity of approximately 20,000centipoises. The similar accelerator of Monsanto, N-2l26-A, which isalso a brown liquid for addition to solvent cements, may also be used.The solid dithiocarbamate Dupont Accelerator 552 is also suitable, butwould have to be milled into the rubber before 4the cement is made.

Selective use of the two types of cement will depend upon the shoeconstruction involved. For instance, the latex type will be preferredfor attaching Abox toes to the inner face of the vamp on all unlinedfootwear, since it is cleaner to handle and will function in cementingmachines. VIn lined footwear, the latex cement can be used on both sidesof the box toe with the vamp, box toe and vamp lining all cementedtogether in the stitching room, or the box toe can be cemented to thevamp with the latex type in .the stitching room, wit-h the lining leftunce-` mented to the box toe until the pulling-over operation. There theoperator, before pulling the shoe, can manually brush a coat of eitherthe latex or the naphtharubber cement over the exposed surface of thebox toe, engaging the lining to the wet cement film and causing allthree parts to become unitary during the course of ensuing shoe makingoperations.

The naphtha-rubber cement may be preferred for use at pulling-over sincemany lined shoes are given a brush coat of rubber cement, called vampformer, between the vamp and the vamp lining in their side portions, andalso directly behind the back edge of the box toe, to help avoid vamplining wrinkles and to hold the lining against the vamp during shoewear. `The naphtha-rubber cement of this invention lwill act as a vampformer as well as to cause curing of the box toe. Thus,'the brushcoating of the vamp and the coating of the box toe can be accomplishedwith a Vsingle cement in a single work step of the operator, as opposedto using the latex type cement to coat the box-toe and a vamp formingcement to unite vamp and vamp lining rearward of the box` toe.

It is `to be understood that either the latex type or the naphtha-rubbertype cement will cure the box toe, and

the latex may be used on one side of the box toe and the naphtha-rubberon the other'. It will be apparent that the vulcanization of the rubbercomponents of the box toe will occur more rapidly if the curing mediaismigrating into the box toe from both sides. with the latex type cementalone, as used in an unlined shoe, will vulcanize more slowly, though ascompletely,

The box toe cemented andere as box toes in lined footwear having eithercement on both surfaces.

Adhesion of the box `toe material to the vamp lining is of a characterto indicate that the adhesive itself becomes vulcanized, even though itcontains no curing agents except the accelerator. It is thought thatenough sulphur may be present at the interface to cure the thin adhesivefilm.

The practice of the shoemaking method involved in the use of `theimpregnated toe stifening blank 10 of this invention is specificallyillustrated in Figs. 1, 2, and 7.

VThe prepared and skived blank having an adhesive coating 14 of activelatex rubber cement containing a room temperature curingultra-accelerator is positioned and applied to the inner surface of thecut shoe vamp 30. Subsequently an upper assembly including a lining 32as well as the vamp 30 and adhered toe stiffener blank 10 are placedover the toe end of a last L having a welt insole 34 secured to the lastbottom. Thereupon the operatorturns back the toe end part of liningV 32and applies an adhesive coating 16 of naphtha-rubber cement containing aroom temperature curing ultra-accelerator to the face of the blank 10engageable by the lining. With the lining 32 adhered to the toe blank1G, the upper assembly is drafted over the last on a pulling overmachine and subsequently finally conformed on a bed lasting machine, andthe marginal edge portions of the lining, blank and Vamp 3i) are securedto the welt insole 34, thus conforming the toe stiiener to the last L asshown in Fig. 5.

It will now be fully understood .that by reason of the room temperaturecuring accelerators used as components of each of the two types ofcement, and the action of such accelerators on the sulphurV contained inthe box toe or other stiifening element material when brought intomutual contact or migrating relation when the cement is applied to thebox toe or other stiffening element, cause the lasted box toe or otherstitfening element progressively to vulcanize to as complete acure-state as would have been obtained in the event that the impregnatedsheet material had been cured before the box toe or other upperstitfening element were cut therefrom` Since the novel sheet material ofthis invention is uncured, though latently curable through the presenceof sulphur in its impregnant, no resistance is otfered to the conformingaction of lasting equipment. ln uncured condition, the shoe stiffenersare limp and extensible, and shape readily to the last. Depending uponwhether the cement and its curing accelerators are presented to one orboth sides of the stitener blank, the cure is progressive to a final endpoint in from 10 to 15 days. This is clear evidence that no degree ofimmediate cure, consistent with the production speeds of normal shoemanufacturing practice, can impair the susceptibility of the box toe toshoe lasting operations.

The shoe stifening material of this invention also has excellentadaptability for stiffening the rearward por. tion ofa shoe upper in theregion where a molded counter is normally used. Consistent with theincreasing demand for flexible box toes, there is a growing interest insoft or flexible heel end structures, particularly for juvenilefootwear.

With specific reference to Figs. 3, 4 and 6, it 'has been -found that avery satisfactory result in this direction can be obtained by cuttingthe quarterj lining blank 26 from leather or imitation leather materialand cementing with either the latex or naphtha-rubbervulcanizing cementVhitherto disclosed the blank of stifening material that has beensuitably skived around its marginal edges, to the inner face of thequarter lining blank in theV region to be stiffened, assembling theunitary quarter lining and stifening blank into the shoe upper 30 bystitching it in place in the usual manner, and thereafter, before theas-l sembling operation in the lasting room, brush coating the inner andpreviously uncemented surface of the stiffening material with thenaphtha-rubber cement to cause the vulcanization of the Vrubberoussaturant contained therein to occur from both surfaces of the stitfeningmaterial blank 20.

In a variation of this method the stilening blank would be cemented inposition on the quarter itself, and directly thereafter the quarterlining would be cemented to the stilfening blank to produce a unitaryconstruction of three parts before the unit becomes attached to the vampto form a completed upper. It has been found that the latex type cementis preferable in this procedure.

In a still further variant, satisfactory results can be obtained bymerely dipping the cut and skived stifening blank into the latex typecement and inserting it into the pocket formed by the bottom free andopen common marginal edges of the quarter and quarter lining. The

cement securely anchors the blank in place and the vulcanizing actionproceeds as heretofore described.

As in the case of the box toes, the shaping and conforming action ofshoemaking operations will cause the counter blank stitening element aswell as the shoe upper to correspond to the contours of the heel endportion of the shoe last. Having been thus self-conformed, the ultimateself-curing attained will cause preservation of the shape imparted bythe dwell on the shoe last. It will be readily appreciated that thecounter portions of shoes stitfened in this manner to a bouncyresilience afford great comfort to growing feet since there is no rigidencasement of the upper portion of the heel bones to restrict footgrowth, and no hard, knife-like edges to abrade against the wearers footwith resulting discomfort. The complete vulcanization of the rubbercomponents of the stif`r`ening material, coupled with its completeconformability in an uncured state is particularly enefcial in thisadditional utilization. The contours essential to the character of theheel portion of the shoe are preserved without progressive collapse andfatigue of the stitr'ening medium that occurs when rubber stiffeningblanks are used in an either completely unvulcanized or only partiallyvulcanized condition.

The term rubber as used broadly herein comprehends synthetic as well asnatural rubber.

Where in the specification and claims reference is made to roomtemperature curing accelerators of the dithiocarbamate type it isspecifically intended to include all dithiocarbamate-producing compoundssuch as those xanthates that when used with an amine form adithiocarbamate, in addition to the commercial dithiocarbamateaccelerator described in the material relating to the specific examplesof adhesive-containing accelerators.

In the formulasl set forth herein satisfactory results are obtainablewhen any combination from the ranges specified is utilized.

The scope of this Ainvention is further demonstrated by the proven factthat a neoprene saturant will cure at room temperature without the useof a curing agent in the saturant by the migration of an xanthatecontained in the adhesive.

The following formulas have been used successfully:

Note: The neoprene is milled with the calcium carbonate and napthenicoil until completely blended whereafter the compound is churned intoluol until a smooth saturable solution is achieved.

Note: The above cement is produced by masterbatching 50 parts ofpremasticated natural rubber with 50 parts of ZBX whereafter thecompound is constructed by using 50 parts of the master batch with 75parts of milled natural rubber resulting in a total of 100 parts rubberto 25 parts of ZBX. The final compound is then churned in 220 parts ofthe petroleum naphtha (type 2220, having a distillation range of 204-220deg. and a Kauri-Butanol index of 45). The butyl alcohol is then added,causing the cement to achieve a desired viscosity.

lt has been further discovered that a neoprene saturant containing acuring agent can also be cured at room temperature by utilizing themigration of an aldehyde amine accelerator contained in the adhesive.

The formulas which follow exemplify such a modification of curingaction:

Saturant Parts by Trade Weight Names Neoprene (chloroprene polymer). 100Type GN. Calcium Carbonate (ller) 40 Light Calcinecl Magnesia (stabil 4Litharge (curing agent) 5 High Napthenic Oil 8 Toluol 200 Note: Thecompounding of the above formula is accomplished in identical fashion tothe description given in the immediately prior saturant formula.

Note: Accelerator 833 which is a butyraldehyde-monobutylaminecondensation product, also a migratory room temperatureultra-accelerator curing medium, and also a Dupont product may besubstituted for Accelerator 808 at equal parts by weight.

Either single or multiple applications of the two neoprene saturants canbe made.

The advantages attained through the use of the stifening blank materialof this invention are without increase in the cost of shoemakingoperations, and are accompanied by such an enhanced superiority of shoeproduct, that any increase in impregnated blank material and cementcosts is more than compensated by satisfaction to the users of suchshoes.

It will be understood that variations, changes, and adaptations can bemade in the invention set forth without departing from rthe principlesthereof and the scope of the appended claims.

Having thus described our invention, what we claim as novel and desireto secure by Letters Patent of the United States is:

1. A prepared shoe upper for lasting in which a particular portion isprovided with a limp, conformable, eXtensible sheet of saturable basematerial impregnated with vulcanizable rubber containing a vulcanizingagent and in which all of said rubber is unvulcanized, said vulcanizingagent being present in amount suicient for subsequent curing of thevulcanizable rubber, and said sheet being adhesively joined to an innersurface of the upper by a rubber-containing cement which includes in itscomposition a room temperature curing accelerator in amount capable incoaction with the said vulcanizing agent of causing complete curing ofthe vulcanizable rubber contained in the sheet whereby the shoe in whichsaid upper is incorporated will have a permanent highly resilientstiifening portion.

2. The combination of claim 1 in which the upper includes a liningmember to which said sheet is also adhesively joined by arubber-containing cement.

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